Condensers and electronic assemblies

ABSTRACT

Provided is a condenser for use in an electronic assembly. The condenser includes a first vertical wall extending in a vertical direction, the first vertical wall defining a first plurality of vertical condensation channels within the first vertical wall, a second vertical wall extending in the vertical direction, the second vertical wall defining a second plurality of vertical condensation channels within the second vertical wall, and a first plurality of fins extending in the vertical direction, each of the first plurality of fins connected to the first vertical wall, the second vertical wall or both the first vertical wall and the second vertical wall.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.16/870,320, filed on May 8, 2020, which claims priority under 35 U.S.C.§ 119(e) to U.S. Provisional Patent Application No. 63/009,789 filed inthe United States Patent and Trademark Office on Apr. 14, 2020, theentire contents of each of which are herein incorporated by reference.

GOVERNMENT LICENSE RIGHTS

This invention was made under CRADA 15-592 between John Deere ElectronicSolutions and the National Renewable Energy Laboratory operated for theUnited States Department of Energy by Alliance for Sustainable Energy,LLC under Prime Contract No. DE-AC36-08GO28308. This invention was madewith government support under Prime Contract No. DE-AC36-08GO28308(CRADA 15-592) awarded by United States Department of Energy by Alliancefor Sustainable Energy, LLC. The Government has certain rights in thisinvention.

BACKGROUND

Example embodiments relate, in general, to condensers for use inelectronic assemblies.

In a power electronics system, heat generating components may includepower semiconductor devices such as silicon insulated-gate bipolartransistors (IGBTs) or silicon carbide (SiC) metal-oxide-semiconductorfield effect transistors (MOSFETs). The thermal design of powerelectronic systems regulates a junction temperature of the powersemiconductor device to achieve a desired longevity and/or reliability.There may generally be two alternate cooling approaches: (1) air-cooledconfigurations and (2) liquid-cooled configurations.

SUMMARY

Because of high heat-flux generated by power semiconductor devices,liquid cooling is often used in an electronics system (e.g., aninverter) for heavy-duty vehicles. However, liquid-cooled configurationsmay be costly and/or complex due to an external pump and radiatorsystems that extract heat from liquid flowing through coolant channelsin the electronics system.

The inventors have discovered an electronic assembly with phase-changecooling of a semiconductor device having a condenser capable ofimproving efficiency of the cooling.

Some example embodiments include condensers having features that mayenable passive two-phase heat transfer for power-dense power electronicsapplications. The condenser may be used in multiple applications thathaving two-phase cooling of a concentrated heat source.

Some example embodiments include a condenser that enables passive, e.g.pumpless, two-phase heat transfer for power-dense power electronics.

Example embodiments include condensers that may enable removal of heat,e.g. heat produced by a semiconductor device, and may have efficientcondensation of a coolant.

According to some example embodiments, there is provided a condenser foruse in an electronic assembly. The condenser includes a first verticalwall extending in a vertical direction, the first vertical wall defininga first plurality of vertical condensation channels within the firstvertical wall, a second vertical wall extending in the verticaldirection, the second vertical wall defining a second plurality ofvertical condensation channels within the second vertical wall, and afirst plurality of fins extending in the vertical direction. Each of thefirst plurality of fins is connected to the first vertical wall, thesecond vertical wall or both the first vertical wall and the secondvertical wall.

BRIEF DESCRIPTION OF DRAWINGS

Example embodiments will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings. FIGS. 1 a-9 b represent non-limiting, example embodiments asdescribed herein.

FIG. 1 a illustrates a perspective view of an electronic assembly,according to some example embodiments.

FIG. 1 b illustrates a cut-out view of the electronic assembly of FIG. 1a.

FIG. 2 a illustrates a perspective view of a condenser, according tosome example embodiments.

FIG. 2 b illustrates a cut-out and zoom-in of region “A” of thecondenser of FIG. 2 a.

FIG. 2 c illustrates a zoom-in of region “B” of the condenser of FIG. 2b.

FIG. 2 d illustrates a schematic view of a vertical condensation channelof FIGS. 2 a -2 c.

FIG. 3 a illustrates a perspective view of a condenser, according tosome example embodiments.

FIG. 3 b illustrates a perspective view of a condenser, according tosome example embodiments.

FIG. 4 a illustrates a perspective view of an electronic assemblyincluding a condenser, a collection manifold, and an evaporator stack,according to some example embodiments.

FIG. 4 b illustrates a schematic view of a connection tube and verticalchannels of FIG. 4 a.

FIGS. 5 a and 5 b illustrate top-down and front views of a condenser,according to some example embodiments.

FIG. 5 c illustrates a front view of a condenser, according to someexample embodiments.

FIG. 6 illustrates a condenser, according to some example embodiments.

FIG. 7 illustrates a perspective view of an electronic assembly,according to some example embodiments.

FIG. 8 illustrates a cut-away view of an electronic assembly, accordingto some example embodiments.

FIG. 9 a illustrates a perspective view of a condenser, a collectionmanifold, a connection, and an evaporator stack, according to someexample embodiments.

FIG. 9 b illustrates a side view of the condenser, the collectionmanifold, the connection, and the evaporator stack of FIG. 9 a ,according to some example embodiments.

FIG. 9 c illustrates a bottom view of the condenser of FIG. 9 a ,according to some example embodiments.

FIG. 9 d illustrates a zoom-in of the region labelled “D” of FIG. 9 c ,according to some example embodiments.

FIG. 9 e illustrates a perspective view of the condenser and thecollection manifold, according to some example embodiments.

FIG. 9 f illustrates a perspective view of the condenser with asee-through view of the collection manifold of FIG. 9 a , according tosome example embodiments.

FIG. 9 g illustrates a cross-sectional view of the condenser, thecollection manifold, the connection, and the evaporator stack of FIG. 9a , according to some example embodiments.

FIG. 10 illustrates an air manifold and a condenser, according to someexample embodiments.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Some example embodiments will now be described more fully with referenceto the accompanying drawings in which some example embodiments areillustrated.

Accordingly, while example embodiments are capable of variousmodifications and alternative forms, embodiments thereof are shown byway of example in the drawings and will herein be described in detail.It should be understood, however, that there is no intent to limitexample embodiments to the particular forms disclosed, but on thecontrary, example embodiments are to cover all modifications,equivalents, and alternatives falling within the scope of the claims.Like numbers refer to like elements throughout the description of thefigures.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of example embodiments. Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.).

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of exampleembodiments. As used herein, the singular forms “a,” “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises,” “comprising,” “includes” and/or “including,” when usedherein, specify the presence of stated features, integers, steps,operations, elements and/or components, but do not preclude the presenceor addition of one or more other features, integers, steps, operations,elements, components and/or groups thereof.

It should also be noted that in some alternative implementations, thefunctions/acts noted may occur out of the order noted in the figures.For example, two figures shown in succession may in fact be executedsubstantially concurrently or may sometimes be executed in the reverseorder, depending upon the functionality/acts involved.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which example embodiments belong. Itwill be further understood that terms, e.g., those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

In a power electronics system, heat generating components include powersemiconductor modules/devices, such as silicon insulated gate bipolartransistors (IGBTs) and/or silicon carbide (SiC) MOSFETs, and/or galliumnitride (Ga) power semiconductor devices. A regulated junctiontemperature of the power semiconductor chips/modules may be beneficialto achieve a desired lifetime and/or reliability goals, particularly inhigh-power-density inverters used for applications such as off-highwayheavy-duty vehicles. Due to high heat-flux generated by powersemiconductor modules in these applications, liquid cooling may be usedin the inverters for heavy-duty vehicles.

Inverter systems may be liquid cooled using a coolant/refrigerant suchas water-ethylene-glycol solutions, e.g. antifreeze. Such cooling mayenable efficient operation of high-powered inverter systems. Liquidcooling may use an external pump and/or radiator systems to extract heatfrom liquid flowing through coolant channels in a power inverter.

According to some example embodiments, liquid cooling may be enabledwith a passive, pumpless air cooling, that may achieve high heattransfer from heat generated during operation of a semiconductormodule/device. For example, refrigerant on a surface of thesemiconductor device may vaporize and change the phase of a refrigerant(e.g. an antifreeze), which may then rise to a condenser, where heat isdissipated in air, e.g. by a fan. Upon condensation of the vapor, therefrigerant changes phase back to liquid, and collects again to beevaporated by the evaporator.

Accordingly, solutions using a 2-phase cooling media usingenvironmentally friendly coolant/refrigerant (for example, R-245fa andHFO-1233zd) may be utilized. However, example embodiments are notlimited thereto. A coolant may be or include a refrigerant with anengineered boiling point.

According to some example embodiments, there is provided a condensercomprising a first vertical wall extending in a vertical direction, thefirst vertical wall defining a first plurality of vertical condensationchannels within the first vertical wall, a second vertical wallextending in the vertical direction, the second vertical wall defining asecond plurality of vertical condensation channels within the secondvertical wall, and a first plurality of fins extending in the verticaldirection, each of the first plurality of fins connected to the firstvertical wall, the second vertical wall or both the first vertical walland the second vertical wall.

According to some example embodiments, the first plurality of verticalcondensation channels are configured to enable condensation of acoolant, the second plurality of vertical condensation channels areconfigured to enable condensation of the coolant, and adjacent ones ofthe first plurality of fins create an airflow opening with surfaces ofthe first vertical wall and surfaces of the second vertical wall, theairflow opening configured to enable airflow along the verticaldirection.

According to some example embodiments, a height of the first verticalwall is greater than a height of at least one of the first plurality offins.

According to some example embodiments, adjacent ones of the firstplurality of fins do not extend in a parallel horizontal direction.

According to some example embodiments, adjacent fins of the firstplurality of extend in a parallel horizontal direction.

According to some example embodiments, a first one of the firstplurality of fins connects to the first vertical wall and to the secondvertical wall.

According to some example embodiments, a first one of the firstplurality of fins contacts the first vertical wall and does not connectto the second vertical wall, a second one of the first plurality of finscontacts the second vertical wall and does not contacts the firstvertical wall, and the first one of the first plurality of fins contactsthe second one of the first plurality of fins.

According to some example embodiments, the condenser further includes athird vertical wall extending in the vertical direction, the thirdvertical wall having a third plurality of vertical condensationchannels, and a second plurality of fins extending in the verticaldirection, each of the second plurality of fins connected to the secondvertical wall and to the third vertical wall.

According to some example embodiments, the first vertical wall includesa connection tube extending in a horizontal direction, the connectiontube defining a hollow horizontal channel, the hollow horizontal channelenabling fluid communication between a first one of the first pluralityof vertical condensation channels and a second one of the firstplurality of vertical condensation channels.

According to some example embodiments, the first vertical wall, thesecond vertical wall, and the first plurality of fins are integral.

According to some example embodiments, the condenser includes a baffleconnected to a bottom of the first vertical wall, the baffle having asurface that extends in a diagonal direction, the diagonal directionbeing diagonal with respect to the vertical direction.

According to some example embodiments, there is provided an electronicassembly comprising at least one semiconductor device on a printedcircuit board, the at least one semiconductor device generating heatduring operation of the at least one semiconductor device, at least oneevaporator on the at least one semiconductor device, the at least oneevaporator configured to evaporate a coolant based on the heat generatedduring the operation of the at least one semiconductor device, acollection manifold on the at least one evaporator, a condenser on thecollection manifold, the condenser including a first vertical walldefining first vertical condensation channels, a second vertical walldefining second condensation channels, a first fin connecting the firstvertical wall to the second vertical wall, and a second fin connectingthe first vertical wall to the second vertical wall, the first fin, thesecond fin, the first vertical wall, and the second vertical walldefining an airflow opening, and at least one fan above the condenser,the at least one fan configured to generate airflow that flowshorizontally over the at least one evaporator and vertically within theairflow opening.

According to some example embodiments, the condenser is configured tocondense the coolant in the first vertical condensation channels and inthe second vertical condensation channels.

According to some example embodiments, wherein a ratio of a number ofevaporator stacks to a number of fans is greater than or equal to threeto one.

According to some example embodiments, the condenser includes aplurality of condenser modules, and each of the plurality of condensermodules have a flat top surface and a diagonal bottom surface, the flattop surface meeting the diagonal bottom surface at an apex.

According to some example embodiments, an apex of a first condensermodule of the plurality of condensers modules meets an apex of a secondcondenser module of the plurality of condenser modules.

According to some example embodiments, there is provided a condenserincluding a plurality of vertical walls, each of the plurality ofvertical walls defining vertical condensation channels, each of thevertical condensation channels configured to convert a phase of acoolant to a liquid-phase, and a collection manifold at a bottom of thecondenser, the collection manifold configured to collect theliquid-phase of the coolant and to provide the liquid-phase of thecoolant to an evaporator.

According to some example embodiments, the collection manifold has atleast four sides, and wherein each of the at least four sides are slopedto drain the liquid-phase of the coolant to the evaporator.

According to some example embodiments, an angle of inclination of eachof the at least four sides is based on a target inclination of theelectronic assembly.

According to some example embodiments, the condenser is integrated withthe collection manifold.

FIG. 1 a illustrates a perspective view of an electronic assembly,according to some example embodiments. FIG. 1 b illustrates a cut-outview of the electronic assembly of FIG. 1 a.

Referring to FIG. 1 a , an electronic assembly 111 may be or correspondto or include an electronic assembly with phase-change cooling of atleast one semiconductor device and/or other heat-generating component.For example, the electronic assembly 111 may include some or all of thecomponents of electronic assemblies described with reference to U.S.Pat. No. 10,278,305, the entire contents of which are hereinincorporated by reference, with differences explained herein.

The electronic assembly 111 may include at least one fan 10. The fan 10may be arranged in a fan section 101 of the electronic assembly 111. Thefan 10 may be arranged horizontally on an upper portion of theelectronic assembly 111.

The fan 10 may include a plurality of blades (not shown). The fan 10 mayrotate the blades in a clockwise, or alternatively, counter-clockwisemanner. Different ones of a plurality of fans 10 may rotate blades inthe same, or in different, directions. Rotation of blades of the fan 10may induce airflow, to be described in more detail below.

The fan section 101 may be positioned over a condenser section 121. Thecondenser section 121 may include at least one condenser (shown in FIG.2 a ), to be described in more detail below. The condenser section 121may be positioned above other components of the electronic assembly 111.

For example, the electronic assembly 111 may include an evaporator stack26. The evaporator stack 26 may include at least one evaporator stacksuch as those described with reference to U.S. Provisional PatentApplication No. 63/009,789.

FIG. 2 a is a perspective view of a condenser 21, FIG. 2 b is a cut-outand zoom-in of region “A” of the condenser 21, FIG. 2 c is a zoom-in ofregion “B” in FIG. 2 b , according to some example embodiments, and FIG.2 d is a schematic view of a vertical condensation channel, according tosome example embodiments.

Referring to FIGS. 2 a-2 d , the condenser 21 may be formed of amaterial, such as a metal and/or an alloy, having thermal propertiesthat enable condensation of a coolant. For example, the condenser 21 maybe formed of at least one of aluminum, copper-nickel alloys, brass,titanium, stainless steel, and/or ferritic stainless steel; however,example embodiments are not limited thereto.

The condenser 21 may be formed in an integrated manner. For example, thecondenser manifold 21 may be formed from a 3D printing process and/orfrom a die-cast molding process; however, example embodiments are notlimited thereto.

The condenser 21 may include a plurality of vertical walls 21VWincluding a first vertical wall 21VW1 and a second vertical wall 26VW2,along with a plurality of fins such as the plurality of fins 21F1.

Each of the plurality of vertical walls 21VW may extend in a horizontaldirection. The horizontal direction may be relative to a bottom surfaceof the electronic assembly 111. Each of the plurality of vertical walls21VW may extend parallel to one another. For example, each of thevertical walls 21VW may extend in a first horizontal direction. Thefirst horizontal direction may correspond to one of the longitudinaldirections of the electronic assembly 111 described above with regardsto FIG. 1 a.

FIG. 2 b illustrates a cut-out and zoom-in of the condenser 21 of FIG. 2a . FIG. 2 b is cut out in a direction parallel to the first and secondhorizontal directions.

Referring to FIG. 2 b , within each of the plurality of vertical walls21VW, there may be a plurality of vertical condensation channels. Forexample, within the first vertical wall 21VW1 there may be a pluralityof first vertical condensation channels 21VC1. Similarly within thesecond vertical wall 21VW2 there may be a plurality of second verticalcondensation channels 21VC2. For example, there may be about 60 to about110, e.g. about 85, first vertical condensation channels 21VC1 in thefirst vertical wall 21VW1, and there may be the same, or a similarnumber, of second vertical condensation channels 21VC2 in the secondvertical wall 21VW2. A number of vertical channels VC1 and a number ofvertical channels VC2 may be determined based on dimensions of thecondenser 21.

Each of the vertical condensation channels such as the verticalcondensation channels 21VC1 and 21VC2 may extend in a verticaldirection. The vertical direction may be perpendicular to the firstand/or second horizontal direction.

Each of the vertical condensation channels such as the verticalcondensation channels 21VC1 and 21VC2 may extend a significant portion,or the entire portion, of the height of the respective vertical walls21VW1 and 21VW2. Each of the vertical condensation channels such as thevertical condensation channels 21VC1 and 21VC2 may be hollow, e.g. mayform a channel and/or a chamber. Each of the vertical condensationchannels such as the vertical condensation channels 21VC1 and 21VC2 mayhave an opening at a top of the respective vertical walls 21VW1 and21VW2, and may have an opening at a bottom of the respective verticalwalls 21VW1 and 21VW2. Dimensions, such as heights of the vertical walls21VW1 and 21VW2, will be described in more detail with reference toFIGS. 3 a -3 c.

Referring to FIG. 2 c , a length 1 of the opening of the verticalcondensation channels 21VC1 and 21VC2 may be about 3 mm, and a width wof the opening of the vertical condensation channels 21VC1 and 21VC2 maybe about 1.5 mm, respectively; however, example embodiments are notlimited thereto. A thickness t of the portion of the vertical walls thatseparate adjacent vertical condensation channels 21VC1 and 21VC2 may beabout 0.75 nm; however, example embodiments are not limited thereto.Furthermore, each of the vertical condensation channels within thevertical condensation channels 21VC1 may have the same, or different,dimensions, e.g. the same and/or different lengths 1, the same and/ordifferent widths w, and the same and/or different thickness t.Similarly, each of the vertical condensation channels within thevertical condensation channels 21VC2 may have the same, or different,dimensions, e.g. the same and/or different lengths 1, the same and/ordifferent widths w, and the same and/or different thickness t.

The vertical condensation channels 21VC1 and 21VC2 are illustrated inFIGS. 2 a-2 d as having rectangular cross-section; however, exampleembodiments are not limited thereto. For example, the verticalcondensation channels 21VC1 and 21VC2 may have the same, or different,shapes. Furthermore the vertical condensation channels 21VC1 and 21VC2may have rectangular openings, or square shapes, or elliptical shapes,or any similar shape. The vertical condensation channels 21VC1 and 21VC2may have openings having various shapes, based on, for example, ease ofmanufacturing.

Each of the vertical condensation channels such as the verticalcondensation channels 21VC1 and 21VC2 may be defined by the walls inwhich they are formed. For example, the vertical condensation channels21VC1 may be or correspond to hollow channels within the vertical wall21VW1, and similarly the vertical condensation channel 21VC2 may be orcorrespond to hollow channels within the vertical wall 21VW2.

As will be explained in more detail below, each of the verticalcondensation channels such as the vertical condensation channels 21VC1and 21VC2 may receive a gas-phase, e.g. a vapor, of a coolant and/orrefrigerant. The vertical condensation channels 21VC1 and 21VC2 maycause condensation of the gas-phase of the coolant, e.g. may cause thecoolant to convert to a liquid-phase. For example, there may benucleation and/or condensation within the sidewalls of the verticalcondensation channels 21VC1 and 21VC2. The coolant may convert toliquid-phase, and may fall down the vertical condensation channels 21VC1and 21VC2, e.g. may fall down sidewalls of the vertical condensationchannels 21VC1 to 21VC2.

Still referring to FIGS. 2 a-2 c , the condenser 21 may include aplurality of fins, such as a plurality of first fins 21F1. The pluralityof fins 21F1 may be connected, e.g. directly connected, to the firstvertical wall 21VW1 and the second vertical wall 21VW2.

Adjacent ones of the plurality of fins may extend in horizontaldirections that are not parallel, and may, for example, correspond towalls of corrugated cardboard. However, example embodiments are notlimited thereto. Adjacent ones of the plurality of fins may extend in aparallel horizontal direction; however, example embodiments are notlimited thereto.

Adjacent ones of the plurality of fins, such as adjacent ones of thefirst plurality of fins 21F1, in conjunction with vertical walls, suchas vertical wall 21VW1 and/or vertical wall 21VW2, may define at leastone vertical opening 210P. The vertical opening 210P may enable airflowto pass through, e.g. to pass through in a vertical manner. As shown inFIG. 2 b , the plurality of fins 21F1, the vertical wall 21VW1 and thevertical wall 21VW2 define a plurality of vertical openings 210P inwhich the cross-section of the opening is triangular. However, exampleembodiments are not limited thereto.

Referring back to FIG. 2 a , there may be airflow AF that is produced bythe fan 10, for example. The airflow AF may initially flow transverse toand on lower portions of the electronic assembly 111, e.g. may flowhorizontally below the condenser 21. The airflow AF may then flowvertically, e.g. air may be pulled vertically, within vertical openingsof the condenser, such as within the vertical opening 210P. For example,the airflow AF may flow in the direction illustrated in FIG. 2 a.

FIG. 2 d illustrates a schematic view a process of coolant evaporationwithin the vertical condensation channel 21VC1, according to someexample embodiments.

Referring to FIG. 2 d , there may be airflow AF generated by a fan, suchas fan 10 illustrated in FIG. 1 a . The airflow AF may rise verticallybetween openings, such as openings 210P illustrated in FIG. 2 b.

A coolant may be in a gas-phase G within the vertical channel 21VC1. Thegas-phase of the coolant may be lighter than air, and the coolant mayrise in the vertical direction.

The coolant may cool, e.g. may cool because of the airflow AF, and maynucleate and condense to the liquid-phase L. The coolant may condensewithin any of the surfaces of the vertical wall 21VW1.

The liquid-phase L of the coolant may fall vertically, e.g. may fall inthe vertical direction. The liquid-phase L may fall down, e.g. may falldown by gravity.

FIG. 3 a illustrates a condenser 21A according to some exampleembodiments.

Descriptions of features similar between the condenser 21 of FIGS. 2 a-2d and the condenser 21A of FIG. 3 a may be omitted for brevity.

Referring to FIG. 3 a , the first vertical wall 21VW1 may have a heighth1, while the first plurality of fins 21F1 may have another height h2.Other vertical walls such as vertical wall 21VW2 may have heights thesame or similar to those of the first vertical wall 21VW1. Other finssuch as 21F2 may have heights the same or similar to those of the firstplurality of fins 21F1.

The height h1 may be greater than the height h2. For example, the heighth1 may be about 45 mm, while the height h2 be about 15 mm.

Each of the first plurality of fins 21F1 may be connected to an upperportion of the first vertical wall 21VW1 and the second vertical wall21VW2, and similarly each of the second plurality of fins 21F2 may beconnected to an upper portion of the first vertical wall 21VW1 and thesecond vertical wall 21VW2. Tops of each of the first plurality of fins21F1 and tops of the second plurality of fins 21F2 may be flush with oneanother, and may also be flush with tops of the second plurality of fins21F2.

Each of the first plurality of fins 21F1 may be connected to both thefirst vertical wall 21VW1 and the second vertical wall 21VW2. Each ofthe second plurality of fins 21F2 may be connected to the secondvertical wall 21VW2, but not connected to the first vertical wall 21VW1.Instead, each of the second plurality of fins 21F2 may be also connectedto a third vertical wall 21VW3.

A number of vertical walls 21VW included in the condenser 21A may beabout 8 to about 30, e.g. may be about 24; however, example embodimentsare not limited thereto. The number of vertical walls 21VW included inthe condenser 21A may be determined, e.g. determined by airflow and/orheat transfer requirements.

FIG. 3 b illustrates a condenser 21B according to some exampleembodiments.

Referring to FIG. 3 b , each of the first plurality of fins 21F1 may beconnected to the first vertical wall 21VW1, but may not be connected tothe second vertical wall 21VW2. Each of the first plurality of fins 21F1may be connected to a first intermediate connection 21IM1. Each of thesecond plurality of fins 21F2 may be connected to the second verticalwall 21VW2, but may not be connected to the third vertical wall 21VW3.Each of the second plurality of fins 21F2 may be connected to the firstintermediate connection 21IM1. A third plurality of fins 21F3 may beconnected to the second vertical wall 21VW2 and to a second intermediateconnection 21IM2. Each of the first intermediate connection 21IM1 andthe second intermediate connection 21IM2 may extend in the samedirection as the first vertical wall 21VW1 and the second vertical wall21VW2. Each of the first intermediate connection 21IM1 and the secondintermediate connection 21IM2 may not include any vertical condensationchannels.

A number of vertical walls 21VW included in the condenser 21B may beabout 4 to about 20, e.g. may be about 12; however, example embodimentsare not limited thereto. The number of vertical walls 21VW included inthe condenser 21B may be determined, e.g. determined by airflow and/orheat transfer requirements.

FIG. 4 a illustrates a perspective view of an electronic assembly 111including a condenser 21, a collection manifold 36, and an evaporatorstack 26, according to some example embodiments. FIG. 4 b illustrates aschematic view of fluid communication between vertical condensationchannels and connection tubes, according to some example embodiments.

Referring to FIG. 4 a , the condenser 21 may correspond to a condenser,such as those described above with reference to FIGS. 1 a-3 b , and/orbelow with reference to FIGS. 5 a -10.

There may be airflow AF, for example airflow AF generated by a fan (notshown). The airflow AF may initially flow horizontally over theelectronic assembly 11, and then vertically, e.g. vertically betweenseparate vertical walls 21VW.

The condenser 21 may include at least one connection tube 21CT. Theremay be a connection tube over each of the plurality of vertical walls21VW. Connection tubes such as the connection tube 21CT may extend in ahorizontal direction along the length of a corresponding vertical wall.For example, the connection tube 21CT may extend over the first verticalwall 21VW1. The connection tube 21CT may be hollow, e.g. may form ahollow horizontal channel. In example embodiments and shown in FIG. 4 a, connection tubes extend over the vertical walls 21VW, respectively.

Referring to FIG. 4 b , each connection tube 21CT may enable fluidcommunication with vertical condensation channels included in respectiveones of the vertical walls 21VW. For example, the connection tube 21CTmay be in communication with, e.g. in fluid communication with, thevertical condensation channels 21VC1 (described above with reference toFIG. 1 b ) included in the first vertical wall 21VW1.

For example, the connection tube 21CT may allow for vapor, e.g.gas-phase G, of the coolant to disperse, e.g. disperse more evenly,among each of the vertical condensation channels 21VC1. There may becondensation, e.g. conversion of the gas-phase G of the coolant to theliquid-phase L of the coolant, along the sides of the verticalcondensation channels 21VC1.

Although the connection tube 21CT is illustrated as cylindrical, exampleembodiments are not limited thereto. A diameter of the connection tube21CT may be about 10 mm; however, example embodiments are not limitedthereto.

Still referring to FIG. 4 a , the condenser 21 may include a base 21BA.The base 21BA may be at a bottom of the condenser 21.

The electronic assembly 111 includes a collection manifold 36 situatedbelow the base 21BA of the condenser 21. There may be an opening withinthe base 21BA to allow fluid communication between the condenser 21 andthe collection manifold 36, to be described in more detail withreference to FIGS. 9 a -9 g.

The collection manifold 36 may collect any liquid-phase of the coolantthat has condensed within the condensation channels such as condensationchannels 21VC1 and 21VC2, described above with respect to FIG. 2 b .Furthermore, there may be additional condensation of the coolant withinthe collection manifold 36.

The collection manifold 36 and the condenser 21 may be formed in anintegrated manner; however, example embodiments are not limited thereto.

There may be an evaporator stack 26 underneath the collection manifold36. For example, there may be an evaporator stack 26 that is connectedto the collection manifold 36.

The evaporator stack 26 may be situated on or directly on asemiconductor device, such as the semiconductor device 20 describedbelow with respect to FIG. 8 . The semiconductor device may generateheat during operation. The heat generated may cause evaporation of acoolant from a liquid-phase to a gas-phase. For example, the evaporatorstack 26 may lead to evaporation of the coolant.

The collection manifold 36 may have sloped surfaces. The collectionmanifold may have at least one surface that is sloped at an angle Theta,for example sloped relative to a lower surface of the electronicassembly 111. The slope Theta may be based on specific requirements ofthe electronic assembly 111. The slope Theta may be a slope that enablescollection of a liquid-phase of the coolant so as to drain the coolantto the evaporator stack 26.

For example, the electronic assembly 111 may be positioned horizontally,or alternatively, at an angle relative to the ground, e.g. to a floor ofa building or a floor of a vehicle such as an electronic vehicle. Theelectronic assembly 111 may be positioned at a target inclinationrelative to the ground or floor.

As described in more detail with reference to FIG. 8 , during operationof the electronic assembly 111, a semiconductor device/module maygenerate heat, and the evaporator stack 26 may cause evaporation of aliquid-phase of a coolant to a gas-phase of the coolant.

The coolant may rise, e.g. may rise vertically relative to the ground.The coolant may condense, e.g. may condense into a liquid-phase L,within the condenser 21 and/or within the collection manifold 36.

After condensation and conversion of the coolant to a liquid-phase L,and collection within the collection manifold 36, the coolant may falldown by gravity, for example down sidewalls of the collection manifold36.

If the electronic assembly 111 is not positioned horizontally relativeto the ground (e.g. relative to a floor of a building or of a vehicle),there may still be evaporation of the coolant from the evaporator stack26, condensation of the coolant within the condenser 21, and collectionof the coolant within the collection manifold 36. The slope Theta may bea slope that enables collection of the liquid-phase of the coolant, ifthe electronic assembly is not positioned horizontally relative to theground.

For example, the electronic assembly 111 may be allowed to be at a sloperelative to the ground of the earth, and the angle Theta may be basedupon the angle relative to which the electronic assembly is situatedwith respect to the ground of the earth.

FIGS. 5 a-5 b illustrate top-down and a cross-sectional view of acondenser 21C, according to some example embodiments. FIG. 5 billustrates a side-view of the condenser 21C taken along cut-line “C-C′”of FIG. 5 a.

Referring to FIGS. 5 a-5 b , the condenser 21 may include a plurality ofvertical walls such as vertical wall 21VW1, each having verticalcondensation channels such as 21VC1.

There may be airflow such as airflow AF. The airflow AF may begenerated, for example, by a fan 10 described above with reference toFIG. 1 a . The airflow AF may rise vertically upward, for example mayrise vertically upward in the vertical openings 210P described abovewith respect to FIG. 2 b.

Referring to FIG. 5 a , the airflow AF may be more pronounced on oneend, e.g. the left end, of the condenser 21. There may be inefficientcooling and/or condensation of a coolant.

FIG. 5 c is a side-view of a condenser 21C, according to some exampleembodiments. The condenser 21C may include features similar to thosediscussed above with respect to FIGS. 1 a-5 b , and descriptions thereofmay be omitted for brevity.

Referring to FIG. 5 c , the condenser 21C may include a baffle 21BF.There may be airflow such as airflow AF. The airflow AF may begenerated, for example, by fan 10. The airflow AF may rise verticallyupward, for example may rise vertically upward in the vertical openings210P described above with respect to FIG. 2 b.

For example, the baffle 21BF may cause the airflow AF to be moreuniform, e.g. may not bunch at one end or another end of the condenser21, and instead may be distributed in a more uniform manner.

The baffle 21BF may be hollow, and may be defined by at least threesurfaces including horizontal surface 21BF1, vertical surface 21BF2, anddiagonal surface 21BF3.

FIG. 6 illustrates a condenser 21D comprising a plurality of condensermodules according to some example embodiments.

Referring to FIG. 6 , the condenser 21D may include a plurality ofcondenser modules such as condenser modules 21M1-21M6. For example,there may be six condenser modules included in condenser 21D.

The condenser 21D may be arranged in an electronic assembly, for examplemay be arranged in the condenser section 121 described above withrespect to FIG. 1 b . The condenser 21D may be arranged below the fansection 101 illustrated above with respect to FIG. 1 b . There may befans, such as fans 10, that provide airflow.

The condenser modules 21M1, 21M2, etc. included in the condenser 21D mayinclude features similar to those described with reference to FIGS. 1 a-10. For example, each of, or at least one of, the condenser module21M1-21M6 may include features similar to condenser 21C described abovewith respect to FIG. 5 b . Accordingly, similar features may be omittedfor brevity.

As illustrated in FIG. 6 , the condenser module 21M1 may have a flat topsurface 21M1FT, and may have a diagonal bottom surface 21M1DB thatextends in a diagonal direction. The flat top surface 21M1FT and thediagonal bottom surface 21M1DB may meet, for example may meet at an apex21M1A.

Similarly, the condenser module 21M2 may have a flat top surface 21M2MFTand a diagonal bottom surface 21M2DB. The flat top surface 21M1FT andthe diagonal bottom surface 21M1DB may meet, for example may meet at anapex 21M2A.

As illustrated in FIG. 6 , the apex 21M1A and the apex 21M2A may beadjacent to one another.

The plurality of condenser modules 21M1-21M6 may form a pattern; forexample, the plurality of condenser modules 21M1-21M6 may form a patternas illustrated in FIG. 6 . There may be a fan such as the fan 10 abovethe condenser 21D. The fan 10 may be roughly the same size as thecondenser 21D.

FIG. 7 illustrates an electronic assembly 111, according to some exampleembodiments. The electronic assembly 111 described in FIG. 7 maycorrespond to the electronic assembly 111 described above with respectto FIGS. 4 a and 4 b.

Referring to FIG. 7 , an electronic assembly 111 may include a fan 10, acondenser 21, and a plurality of evaporator stacks 26. There may be atleast one collection manifold (not shown) between the condenser 21 andthe plurality of evaporator stacks 26.

The fan 10 may have a diameter d of about 250 mm; however, exampleembodiments are not limited thereto.

The condenser 21 may correspond to at least one of the condensersdescribed above with respect to FIGS. 1-6 . For example, the condenser21 may correspond to the condenser 21D described above with respect toFIG. 6 .

There may be a number of evaporator stacks 26 included in the electronicassembly 111. For example, as illustrated in FIG. 7 , according toexample embodiments, one fan 10 may be able to support sufficientairflow to provide condensation of a gas-phase of a coolant that hasbeen evaporated by up to three evaporator stacks 26. A ratio of a numberof fans 10 to a number of evaporator stacks 26 may be about one tothree; however, example embodiments are not limited thereto.

FIG. 8 illustrates a cut-away view of an electronic assembly 111,according to some example embodiments.

As illustrated in FIG. 8 , an electronic assembly 111 may include acondenser 21, a collection manifold 36, a semiconductor device 20, andan evaporator stack 26.

The semiconductor device 20 may be include in a printed circuit board42. The semiconductor device 20 may be or include a power-densesemiconductor device, such as an insulated-gate bipolar transistor(IGBT) semiconductor device. The electronic assembly 111 may be orcorrespond to an inverter, for example an inverter for use in anelectronic vehicle.

The semiconductor device 20 may generate heat, for example, may generateheat during operation. The heat generated by the semiconductor device 20may rise through the evaporator stack 26. The evaporator stack 26 maycause evaporation (e.g. boiling) of a coolant, for example may cause acoolant to change from a liquid-phase L to a gas-phase G

The gas-phase G of the coolant may rise through the collection manifold36. The coolant may cool and condense to the liquid-phase L within thecollection manifold 36. The gas-phase G of the coolant may further riseinto the condenser 21. For example, the gas-phase G of the coolant mayrise through openings on the bottom of the condenser 21, to be describedin more detail with reference to FIG. 9 b.

When the gas-phase G of the coolant enters the condenser 21, thegas-phase G may cool. For example, the gas-phase G may cool from airflowAF provided by fans.

The gas-phase G of the coolant may condense within the verticalcondensation channels of the condenser 21, for example may rise throughthe vertical condensation channels 21VC1 and 21VC2 described above withreference to FIG. 2 b.

The gas-phase G of the coolant in the condenser 21 may be cooled, forexample may be cooled by airflow produced by a fan (not shown), such asthe airflow AF generated by the fan 10 described above with reference toFIGS. 1 a -7. Upon cooling, the coolant may condense, for example maycondense in the condenser 21 and/or in the collection manifold 36.

Upon condensing into the liquid-phase L, the coolant may fall backthrough the collection manifold 36, and may be resupplied to a surfaceof, e.g. a top surface of, the semiconductor chip 20, through theevaporator stack 26.

Accordingly, there may be a passive two-phase cooling of the electronicassembly 111.

FIG. 9 a illustrates a perspective view of a condenser, a collectionmanifold, a connection, and an evaporator stack, according to someexample embodiments. FIG. 9 b illustrates a side view of the condenser,the collection manifold, the connection, and the evaporator stack ofFIG. 9 a , according to some example embodiments. FIG. 9 c illustrates abottom view of the condenser manifold of FIG. 9 a , according to someexample embodiments. FIG. 9 d illustrates a zoom-in of the regionlabelled “D” of FIG. 9 c , according to some example embodiments. FIG. 9e illustrates a perspective view of the condenser and the collectionmanifold, according to some example embodiments. FIG. 9 f illustrates aperspective view of the condenser with a see-through view of thecollection manifold of FIG. 9 a , according to some example embodiments.FIG. 9 g illustrates a cross-sectional view of the condenser, thecollection manifold, the connection, and the evaporator stack of FIG. 9a , according to some example embodiments.

Referring to FIGS. 9 a-9 b , a condenser 21 may be situated on acollection manifold 36A. The condenser 21 may be or correspond to one ofthe condensers described above with respect to FIGS. 1 a -8. Thecondenser 21 may include vertical walls 21VW and fins 21F.

The collection manifold 36A may correspond to the collection manifold 36described above with reference to FIG. 8 . Alternatively, the collectionmanifold 36A may not have sloped surfaces.

The condenser 21 may include a base 21BA. The base 21BA may beconfigured to be situated on top of the collection manifold 36A.

The collection manifold 36A may be situated on top of a connection 53.The connection 53 may be situated on top of an evaporator stack 26.

Referring to FIGS. 9 c and 9 d , within the base 21BA there may be aplurality of refrigerant channels 21RC. For example, there may be twosets of refrigerant channels 21RC within the base 21BA.

The refrigerant channels 21RC may allow for communication with, e.g.fluid communication with, vertical condensation chambers within thevertical walls 21VW of the condenser 21. For example, the refrigerantchannels 21RC may be connected to, or in fluid communication with, thevertical condensation channels 26VC1, described with reference to FIG. 9g.

Around a first set of refrigerant channels 21RC, there may be a firstO-ring 210R1. Similarly, around a second set of refrigerant channels21RC, there may be a second O-ring 210R2. The first O-ring 210R1 and thesecond O-ring 210R2 may allow for a secure fit between the condenser 21and the collection manifold 36A. The first O-ring 210R1 and the secondO-ring 210R2 may provide a seal between the refrigerant channels 21RCand the vertical channels such as vertical channels 21VC1 within thevertical walls 21VW.

The refrigerant channels 21RC may enable fluid communication, e.g. bothgas-phase and liquid-phase communication, between the collectionmanifold 36A and vertical channels within vertical walls of thecondenser 21, e.g. within the vertical channels 21VC1 within the firstvertical wall 21VW1. The condenser 21 may correspond to one of thecondensers described above with reference to FIGS. 1 a -8.

Referring to FIG. 9 e , at a bottom of the collection manifold 36A,there may be a recess 36R. The recess 36R may be a recess foraccommodating a connection to an evaporator stack 26, such as theconnection 53 to the evaporator stack 26 of FIG. 9 a.

Referring to FIGS. 9 f and 9 g , within the collection manifold 36Athere may be a number of connecting tubes 36P. Each of the connectingtubes 36P may have a first opening 36P01 in fluid communication with arefrigerant channel 21RC, and may have a second opening 36P02 in fluidcommunication with a recess 36R.

The collection manifold 36A may be connected to the connection 53 and/ordirectly to the evaporator stack 26. A semiconductor device (not shown)may generate heat during operation. The semiconductor device may heatthe evaporator stack 26. The evaporator stack 26 may causeevaporation/boiling of a liquid-phase L of a coolant into a gas-phase G.The gas-phase G of the coolant may rise up, e.g. may rise up through theconnection 53 into the second openings 36P02 of the connection tube 36P.The gas-phase G of the coolant may enter the refrigerant channels 21RCthrough the first openings 36P01, and may rise up through the verticalchannels 21VC within the vertical walls 21VW. The coolant may be cooledby airflow, e.g. vertical airflow AF within the condenser 21 on oppositesides of the vertical wall 21VW than that of the vertical channels21VC1, and condense back to a liquid-phase L within the verticalchannels 21VC1, and may fall back through gravity to the evaporatorstack 26.

FIG. 10 is an illustration of a connection of an air manifold 61 and acondenser 21.

The example embodiment described with reference to FIG. 10 may beuseful, for example, during testing, prototyping, and/orcharacterization of condensers and/or evaporators.

Referring to FIG. 10 , the air manifold 61 may be situated on top of thecondenser 21. There may be components 61W that surround vertical walls,such as vertical walls 21VW, of the condenser 21. The air manifold 61may fit around the vertical walls 21VW of the condenser 21.

The air manifold 61 may generate airflow AF. The airflow AF may flowbetween vertical walls within the condenser 21, e.g. between verticalwalls 21VW1 and vertical wall 21VW2.

As described above with reference to FIGS. 1 a -10, there may bepumpless, passive evaporation and condensation of a coolant.Furthermore, use of the air manifold 61 may enable rapidcharacterization and prototyping of a condenser 21, according to someexample embodiments.

Having described various example embodiments, it will become apparentthat various modifications can be made without departing from the scopeof the invention as defined in the accompanying claims.

What is claimed is:
 1. An electronic assembly comprising: at least onesemiconductor device on a printed circuit board, the at least onesemiconductor device generating heat during operation of the at leastone semiconductor device; at least one evaporator on the at least onesemiconductor device, the at least one evaporator configured toevaporate a coolant based on the heat generated during the operation ofthe at least one semiconductor device; a collection manifold on the atleast one evaporator; a condenser on the collection manifold, thecondenser including a first vertical wall defining first verticalcondensation channels, a second vertical wall defining secondcondensation channels, a first fin connecting the first vertical wall tothe second vertical wall, and a second fin connecting the first verticalwall to the second vertical wall, the first fin, the second fin, thefirst vertical wall, and the second vertical wall defining an airflowopening; and at least one fan above the condenser, the at least one fanconfigured to generate airflow that flows horizontally over the at leastone evaporator and vertically within the airflow opening.
 2. Theelectronic assembly of claim 1, wherein the condenser is configured tocondense the coolant in the first vertical condensation channels and inthe second vertical condensation channels.
 3. The electronic assembly ofclaim 1, wherein a ratio of a number of evaporator stacks to a number offans is greater than or equal to three to one.
 4. The electronicassembly of claim 1, wherein the condenser includes a plurality ofcondenser modules, and each of the plurality of condenser modules have aflat top surface and a diagonal bottom surface, the flat top surfacemeeting the diagonal bottom surface at an apex.
 5. The electronicassembly of claim 4, wherein an apex of a first condenser module of theplurality of condensers modules meets an apex of a second condensermodule of the plurality of condenser modules.
 6. An electronic assemblycomprising: a condenser including a plurality of vertical walls, each ofthe plurality of vertical walls defining vertical condensation channels,each of the vertical condensation channels configured to convert a phaseof a coolant to a liquid-phase; and a collection manifold at a bottom ofthe condenser, the collection manifold configured to collect theliquid-phase of the coolant and to provide the liquid-phase of thecoolant to an evaporator.
 7. The electronic assembly of claim 6, whereinthe collection manifold has at least four sides, and wherein each of theat least four sides are sloped to drain the liquid-phase of the coolantto the evaporator.
 8. The electronic assembly of claim 7, wherein anangle of inclination of each of the at least four sides is based on atarget inclination of the electronic assembly.
 9. The electronicassembly of claim 6, wherein the condenser is integrated with thecollection manifold.